diff mbox

ARM: errata: workaround Cortex-A9 errata 761320 and 794072

Message ID 1396298072-13254-2-git-send-email-nitin.garg@freescale.com
State New
Headers show

Commit Message

Nitin Garg March 31, 2014, 8:34 p.m. UTC
Add workaround for Cortex-A9 errata 761320 ([present on r0,
r1, r2, r3) and 794072 (present on all revisions). These are
Category B, present on SMP systems.

Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
---
 arch/arm/Kconfig          |   23 +++++++++++++++++++++++
 arch/arm/mach-imx/Kconfig |    2 ++
 arch/arm/mm/proc-v7.S     |   11 +++++++++++
 3 files changed, 36 insertions(+), 0 deletions(-)

Comments

Rob Herring April 2, 2014, 1:11 a.m. UTC | #1
On Mon, Mar 31, 2014 at 3:34 PM, Nitin Garg <nitin.garg@freescale.com> wrote:
> Add workaround for Cortex-A9 errata 761320 ([present on r0,
> r1, r2, r3) and 794072 (present on all revisions). These are
> Category B, present on SMP systems.

These work-arounds don't work on non-secure systems which don't have
access to the diagnostic register. There is no architectural way to
determine secure vs. non-secure mode. It's been discussed before and
decided that these types of work-arounds must go into the bootloader
or firmware.

Rob

>
> Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
> ---
>  arch/arm/Kconfig          |   23 +++++++++++++++++++++++
>  arch/arm/mach-imx/Kconfig |    2 ++
>  arch/arm/mm/proc-v7.S     |   11 +++++++++++
>  3 files changed, 36 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index a48712e..f8464ff 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1301,6 +1301,29 @@ config ARM_ERRATA_751472
>           operation is received by a CPU before the ICIALLUIS has completed,
>           potentially leading to corrupted entries in the cache or TLB.
>
> +config ARM_ERRATA_794072
> +       bool "ARM errata: A short loop including a DMB instruction might cause a denial of service"
> +       depends on CPU_V7 && SMP
> +       help
> +          This option enables the workaround for the 794072 Cortex-A9
> +          (all revisions). A processor which continuously executes a short
> +          loop containing a DMB instruction might prevent a CP15 operation
> +          broadcast by another processor making further progress, causing
> +          a denial of service. This erratum can be worked around by setting
> +          bit[4] of the undocumented Diagnostic Control Register to 1.
> +
> +config ARM_ERRATA_761320
> +       bool "Full cache line writes to the same memory region from at least two processors might deadlock processor"
> +       depends on CPU_V7 && SMP
> +       help
> +         This option enables the workaround for the 761320 Cortex-A9 (r0..r3).
> +         Under very rare circumstances, full cache line writes
> +         from (at least) 2 processors on cache lines in hazard with
> +         other requests may cause arbitration issues in the SCU,
> +         leading to processor deadlock. This erratum can be
> +         worked around by setting bit[21] of the undocumented
> +         Diagnostic Control Register to 1.
> +
>  config PL310_ERRATA_753970
>         bool "PL310 errata: cache sync operation may be faulty"
>         depends on CACHE_PL310
> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> index 5740296d..19690c2 100644
> --- a/arch/arm/mach-imx/Kconfig
> +++ b/arch/arm/mach-imx/Kconfig
> @@ -794,6 +794,8 @@ config SOC_IMX6
>  config SOC_IMX6Q
>         bool "i.MX6 Quad/DualLite support"
>         select ARM_ERRATA_764369 if SMP
> +       select ARM_ERRATA_794072 if SMP
> +       select ARM_ERRATA_761320 if SMP
>         select HAVE_ARM_SCU if SMP
>         select HAVE_ARM_TWD if SMP
>         select MIGHT_HAVE_PCI
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> index 195731d..b5e5386 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -337,6 +337,17 @@ __v7_setup:
>         mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
>  1:
>  #endif
> +#ifdef CONFIG_ARM_ERRATA_794072
> +       mrc     p15, 0, r10, c15, c0, 1         @ read diagnostic register
> +       orr     r10, r10, #1 << 4               @ set bit #4
> +       mcr     p15, 0, r10, c15, c0, 1         @ write diagnostic register
> +#endif
> +#ifdef CONFIG_ARM_ERRATA_761320
> +       cmp     r6, #0x40                       @ present prior to r4p0
> +       mrclt   p15, 0, r10, c15, c0, 1         @ read diagnostic register
> +       orrlt   r10, r10, #1 << 21              @ set bit #21
> +       mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
> +#endif
>
>         /* Cortex-A15 Errata */
>  3:     ldr     r10, =0x00000c0f                @ Cortex-A15 primary part number
> --
> 1.7.4.1
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Nitin Garg April 2, 2014, 1:18 a.m. UTC | #2
Hi Rob,

Thanks for reply. In that case, I wonder why there is already code which access the diagnostic register. Pls see:
arch/arm/mm/proc-v7.S: __v7_setup
CONFIG_ARM_ERRATA_742230
CONFIG_ARM_ERRATA_742231
CONFIG_ARM_ERRATA_743622
CONFIG_ARM_ERRATA_751472

Regards,
Nitin Garg


-----Original Message-----
From: Rob Herring [mailto:robherring2@gmail.com] 
Sent: Tuesday, April 01, 2014 8:12 PM
To: Garg Nitin-B37173
Cc: Russell King - ARM Linux; linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: errata: workaround Cortex-A9 errata 761320 and 794072

On Mon, Mar 31, 2014 at 3:34 PM, Nitin Garg <nitin.garg@freescale.com> wrote:
> Add workaround for Cortex-A9 errata 761320 ([present on r0, r1, r2, 
> r3) and 794072 (present on all revisions). These are Category B, 
> present on SMP systems.

These work-arounds don't work on non-secure systems which don't have access to the diagnostic register. There is no architectural way to determine secure vs. non-secure mode. It's been discussed before and decided that these types of work-arounds must go into the bootloader or firmware.

Rob

>
> Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
> ---
>  arch/arm/Kconfig          |   23 +++++++++++++++++++++++
>  arch/arm/mach-imx/Kconfig |    2 ++
>  arch/arm/mm/proc-v7.S     |   11 +++++++++++
>  3 files changed, 36 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 
> a48712e..f8464ff 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1301,6 +1301,29 @@ config ARM_ERRATA_751472
>           operation is received by a CPU before the ICIALLUIS has completed,
>           potentially leading to corrupted entries in the cache or TLB.
>
> +config ARM_ERRATA_794072
> +       bool "ARM errata: A short loop including a DMB instruction might cause a denial of service"
> +       depends on CPU_V7 && SMP
> +       help
> +          This option enables the workaround for the 794072 Cortex-A9
> +          (all revisions). A processor which continuously executes a short
> +          loop containing a DMB instruction might prevent a CP15 operation
> +          broadcast by another processor making further progress, causing
> +          a denial of service. This erratum can be worked around by setting
> +          bit[4] of the undocumented Diagnostic Control Register to 1.
> +
> +config ARM_ERRATA_761320
> +       bool "Full cache line writes to the same memory region from at least two processors might deadlock processor"
> +       depends on CPU_V7 && SMP
> +       help
> +         This option enables the workaround for the 761320 Cortex-A9 (r0..r3).
> +         Under very rare circumstances, full cache line writes
> +         from (at least) 2 processors on cache lines in hazard with
> +         other requests may cause arbitration issues in the SCU,
> +         leading to processor deadlock. This erratum can be
> +         worked around by setting bit[21] of the undocumented
> +         Diagnostic Control Register to 1.
> +
>  config PL310_ERRATA_753970
>         bool "PL310 errata: cache sync operation may be faulty"
>         depends on CACHE_PL310
> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig 
> index 5740296d..19690c2 100644
> --- a/arch/arm/mach-imx/Kconfig
> +++ b/arch/arm/mach-imx/Kconfig
> @@ -794,6 +794,8 @@ config SOC_IMX6
>  config SOC_IMX6Q
>         bool "i.MX6 Quad/DualLite support"
>         select ARM_ERRATA_764369 if SMP
> +       select ARM_ERRATA_794072 if SMP
> +       select ARM_ERRATA_761320 if SMP
>         select HAVE_ARM_SCU if SMP
>         select HAVE_ARM_TWD if SMP
>         select MIGHT_HAVE_PCI
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 
> 195731d..b5e5386 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -337,6 +337,17 @@ __v7_setup:
>         mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
>  1:
>  #endif
> +#ifdef CONFIG_ARM_ERRATA_794072
> +       mrc     p15, 0, r10, c15, c0, 1         @ read diagnostic register
> +       orr     r10, r10, #1 << 4               @ set bit #4
> +       mcr     p15, 0, r10, c15, c0, 1         @ write diagnostic register
> +#endif
> +#ifdef CONFIG_ARM_ERRATA_761320
> +       cmp     r6, #0x40                       @ present prior to r4p0
> +       mrclt   p15, 0, r10, c15, c0, 1         @ read diagnostic register
> +       orrlt   r10, r10, #1 << 21              @ set bit #21
> +       mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
> +#endif
>
>         /* Cortex-A15 Errata */
>  3:     ldr     r10, =0x00000c0f                @ Cortex-A15 primary part number
> --
> 1.7.4.1
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Rob Herring April 2, 2014, 2:37 a.m. UTC | #3
On Tue, Apr 1, 2014 at 8:18 PM, Nitin Garg <nitin.garg@freescale.com> wrote:
> Hi Rob,

Please follow mailing list rules and don't top post.

> Thanks for reply. In that case, I wonder why there is already code which access the diagnostic register. Pls see:
> arch/arm/mm/proc-v7.S: __v7_setup
> CONFIG_ARM_ERRATA_742230
> CONFIG_ARM_ERRATA_742231
> CONFIG_ARM_ERRATA_743622
> CONFIG_ARM_ERRATA_751472

Perhaps you should look at this commit:

commit 62e4d357aae0c7438c537bdb1c86909d7cac2663
Author: Rob Herring <rob.herring@calxeda.com>
Date:   Fri Dec 21 22:42:40 2012 +0100

    ARM: 7609/1: disable errata work-arounds which access secure registers

    In order to support secure and non-secure platforms in multi-platform
    kernels, errata work-arounds that access secure only registers need to
    be disabled. Make all the errata options that fit in this category
    depend on !CONFIG_ARCH_MULTIPLATFORM.

    This will effectively remove the errata options as platforms are
    converted over to multi-platform.

    Signed-off-by: Rob Herring <rob.herring@calxeda.com>
    Acked-by: Tony Lindgren <tony@atomide.com>
    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>


And one hint, the solution for you is not adding "depends on
!CONFIG_ARCH_MULTIPLATFORM". Adding that for something new will not
get accepted.

Once exynos is converted to multi-platform, we may be able to actually
remove all these A9 errata as there may not be any more non
multi-platform A9 or A15 based platforms.

Rob

>
> Regards,
> Nitin Garg
>
>
> -----Original Message-----
> From: Rob Herring [mailto:robherring2@gmail.com]
> Sent: Tuesday, April 01, 2014 8:12 PM
> To: Garg Nitin-B37173
> Cc: Russell King - ARM Linux; linux-arm-kernel@lists.infradead.org
> Subject: Re: [PATCH] ARM: errata: workaround Cortex-A9 errata 761320 and 794072
>
> On Mon, Mar 31, 2014 at 3:34 PM, Nitin Garg <nitin.garg@freescale.com> wrote:
>> Add workaround for Cortex-A9 errata 761320 ([present on r0, r1, r2,
>> r3) and 794072 (present on all revisions). These are Category B,
>> present on SMP systems.
>
> These work-arounds don't work on non-secure systems which don't have access to the diagnostic register. There is no architectural way to determine secure vs. non-secure mode. It's been discussed before and decided that these types of work-arounds must go into the bootloader or firmware.
>
> Rob
>
>>
>> Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
>> ---
>>  arch/arm/Kconfig          |   23 +++++++++++++++++++++++
>>  arch/arm/mach-imx/Kconfig |    2 ++
>>  arch/arm/mm/proc-v7.S     |   11 +++++++++++
>>  3 files changed, 36 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index
>> a48712e..f8464ff 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -1301,6 +1301,29 @@ config ARM_ERRATA_751472
>>           operation is received by a CPU before the ICIALLUIS has completed,
>>           potentially leading to corrupted entries in the cache or TLB.
>>
>> +config ARM_ERRATA_794072
>> +       bool "ARM errata: A short loop including a DMB instruction might cause a denial of service"
>> +       depends on CPU_V7 && SMP
>> +       help
>> +          This option enables the workaround for the 794072 Cortex-A9
>> +          (all revisions). A processor which continuously executes a short
>> +          loop containing a DMB instruction might prevent a CP15 operation
>> +          broadcast by another processor making further progress, causing
>> +          a denial of service. This erratum can be worked around by setting
>> +          bit[4] of the undocumented Diagnostic Control Register to 1.
>> +
>> +config ARM_ERRATA_761320
>> +       bool "Full cache line writes to the same memory region from at least two processors might deadlock processor"
>> +       depends on CPU_V7 && SMP
>> +       help
>> +         This option enables the workaround for the 761320 Cortex-A9 (r0..r3).
>> +         Under very rare circumstances, full cache line writes
>> +         from (at least) 2 processors on cache lines in hazard with
>> +         other requests may cause arbitration issues in the SCU,
>> +         leading to processor deadlock. This erratum can be
>> +         worked around by setting bit[21] of the undocumented
>> +         Diagnostic Control Register to 1.
>> +
>>  config PL310_ERRATA_753970
>>         bool "PL310 errata: cache sync operation may be faulty"
>>         depends on CACHE_PL310
>> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
>> index 5740296d..19690c2 100644
>> --- a/arch/arm/mach-imx/Kconfig
>> +++ b/arch/arm/mach-imx/Kconfig
>> @@ -794,6 +794,8 @@ config SOC_IMX6
>>  config SOC_IMX6Q
>>         bool "i.MX6 Quad/DualLite support"
>>         select ARM_ERRATA_764369 if SMP
>> +       select ARM_ERRATA_794072 if SMP
>> +       select ARM_ERRATA_761320 if SMP
>>         select HAVE_ARM_SCU if SMP
>>         select HAVE_ARM_TWD if SMP
>>         select MIGHT_HAVE_PCI
>> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index
>> 195731d..b5e5386 100644
>> --- a/arch/arm/mm/proc-v7.S
>> +++ b/arch/arm/mm/proc-v7.S
>> @@ -337,6 +337,17 @@ __v7_setup:
>>         mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
>>  1:
>>  #endif
>> +#ifdef CONFIG_ARM_ERRATA_794072
>> +       mrc     p15, 0, r10, c15, c0, 1         @ read diagnostic register
>> +       orr     r10, r10, #1 << 4               @ set bit #4
>> +       mcr     p15, 0, r10, c15, c0, 1         @ write diagnostic register
>> +#endif
>> +#ifdef CONFIG_ARM_ERRATA_761320
>> +       cmp     r6, #0x40                       @ present prior to r4p0
>> +       mrclt   p15, 0, r10, c15, c0, 1         @ read diagnostic register
>> +       orrlt   r10, r10, #1 << 21              @ set bit #21
>> +       mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
>> +#endif
>>
>>         /* Cortex-A15 Errata */
>>  3:     ldr     r10, =0x00000c0f                @ Cortex-A15 primary part number
>> --
>> 1.7.4.1
>>
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>
Nitin Garg April 2, 2014, 2:39 a.m. UTC | #4
Got it, Thanks!

Regards,
Nitin Garg


-----Original Message-----
From: Rob Herring [mailto:robherring2@gmail.com] 
Sent: Tuesday, April 01, 2014 9:38 PM
To: Garg Nitin-B37173
Cc: Russell King - ARM Linux; linux-arm-kernel@lists.infradead.org; Catalin Marinas; Arnd Bergmann
Subject: Re: [PATCH] ARM: errata: workaround Cortex-A9 errata 761320 and 794072

On Tue, Apr 1, 2014 at 8:18 PM, Nitin Garg <nitin.garg@freescale.com> wrote:
> Hi Rob,

Please follow mailing list rules and don't top post.

> Thanks for reply. In that case, I wonder why there is already code which access the diagnostic register. Pls see:
> arch/arm/mm/proc-v7.S: __v7_setup
> CONFIG_ARM_ERRATA_742230
> CONFIG_ARM_ERRATA_742231
> CONFIG_ARM_ERRATA_743622
> CONFIG_ARM_ERRATA_751472

Perhaps you should look at this commit:

commit 62e4d357aae0c7438c537bdb1c86909d7cac2663
Author: Rob Herring <rob.herring@calxeda.com>
Date:   Fri Dec 21 22:42:40 2012 +0100

    ARM: 7609/1: disable errata work-arounds which access secure registers

    In order to support secure and non-secure platforms in multi-platform
    kernels, errata work-arounds that access secure only registers need to
    be disabled. Make all the errata options that fit in this category
    depend on !CONFIG_ARCH_MULTIPLATFORM.

    This will effectively remove the errata options as platforms are
    converted over to multi-platform.

    Signed-off-by: Rob Herring <rob.herring@calxeda.com>
    Acked-by: Tony Lindgren <tony@atomide.com>
    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>


And one hint, the solution for you is not adding "depends on !CONFIG_ARCH_MULTIPLATFORM". Adding that for something new will not get accepted.

Once exynos is converted to multi-platform, we may be able to actually remove all these A9 errata as there may not be any more non multi-platform A9 or A15 based platforms.

Rob

>
> Regards,
> Nitin Garg
>
>
> -----Original Message-----
> From: Rob Herring [mailto:robherring2@gmail.com]
> Sent: Tuesday, April 01, 2014 8:12 PM
> To: Garg Nitin-B37173
> Cc: Russell King - ARM Linux; linux-arm-kernel@lists.infradead.org
> Subject: Re: [PATCH] ARM: errata: workaround Cortex-A9 errata 761320 
> and 794072
>
> On Mon, Mar 31, 2014 at 3:34 PM, Nitin Garg <nitin.garg@freescale.com> wrote:
>> Add workaround for Cortex-A9 errata 761320 ([present on r0, r1, r2,
>> r3) and 794072 (present on all revisions). These are Category B, 
>> present on SMP systems.
>
> These work-arounds don't work on non-secure systems which don't have access to the diagnostic register. There is no architectural way to determine secure vs. non-secure mode. It's been discussed before and decided that these types of work-arounds must go into the bootloader or firmware.
>
> Rob
>
>>
>> Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
>> ---
>>  arch/arm/Kconfig          |   23 +++++++++++++++++++++++
>>  arch/arm/mach-imx/Kconfig |    2 ++
>>  arch/arm/mm/proc-v7.S     |   11 +++++++++++
>>  3 files changed, 36 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 
>> a48712e..f8464ff 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -1301,6 +1301,29 @@ config ARM_ERRATA_751472
>>           operation is received by a CPU before the ICIALLUIS has completed,
>>           potentially leading to corrupted entries in the cache or TLB.
>>
>> +config ARM_ERRATA_794072
>> +       bool "ARM errata: A short loop including a DMB instruction might cause a denial of service"
>> +       depends on CPU_V7 && SMP
>> +       help
>> +          This option enables the workaround for the 794072 Cortex-A9
>> +          (all revisions). A processor which continuously executes a short
>> +          loop containing a DMB instruction might prevent a CP15 operation
>> +          broadcast by another processor making further progress, causing
>> +          a denial of service. This erratum can be worked around by setting
>> +          bit[4] of the undocumented Diagnostic Control Register to 1.
>> +
>> +config ARM_ERRATA_761320
>> +       bool "Full cache line writes to the same memory region from at least two processors might deadlock processor"
>> +       depends on CPU_V7 && SMP
>> +       help
>> +         This option enables the workaround for the 761320 Cortex-A9 (r0..r3).
>> +         Under very rare circumstances, full cache line writes
>> +         from (at least) 2 processors on cache lines in hazard with
>> +         other requests may cause arbitration issues in the SCU,
>> +         leading to processor deadlock. This erratum can be
>> +         worked around by setting bit[21] of the undocumented
>> +         Diagnostic Control Register to 1.
>> +
>>  config PL310_ERRATA_753970
>>         bool "PL310 errata: cache sync operation may be faulty"
>>         depends on CACHE_PL310
>> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig 
>> index 5740296d..19690c2 100644
>> --- a/arch/arm/mach-imx/Kconfig
>> +++ b/arch/arm/mach-imx/Kconfig
>> @@ -794,6 +794,8 @@ config SOC_IMX6
>>  config SOC_IMX6Q
>>         bool "i.MX6 Quad/DualLite support"
>>         select ARM_ERRATA_764369 if SMP
>> +       select ARM_ERRATA_794072 if SMP
>> +       select ARM_ERRATA_761320 if SMP
>>         select HAVE_ARM_SCU if SMP
>>         select HAVE_ARM_TWD if SMP
>>         select MIGHT_HAVE_PCI
>> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index
>> 195731d..b5e5386 100644
>> --- a/arch/arm/mm/proc-v7.S
>> +++ b/arch/arm/mm/proc-v7.S
>> @@ -337,6 +337,17 @@ __v7_setup:
>>         mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
>>  1:
>>  #endif
>> +#ifdef CONFIG_ARM_ERRATA_794072
>> +       mrc     p15, 0, r10, c15, c0, 1         @ read diagnostic register
>> +       orr     r10, r10, #1 << 4               @ set bit #4
>> +       mcr     p15, 0, r10, c15, c0, 1         @ write diagnostic register
>> +#endif
>> +#ifdef CONFIG_ARM_ERRATA_761320
>> +       cmp     r6, #0x40                       @ present prior to r4p0
>> +       mrclt   p15, 0, r10, c15, c0, 1         @ read diagnostic register
>> +       orrlt   r10, r10, #1 << 21              @ set bit #21
>> +       mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register
>> +#endif
>>
>>         /* Cortex-A15 Errata */
>>  3:     ldr     r10, =0x00000c0f                @ Cortex-A15 primary part number
>> --
>> 1.7.4.1
>>
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>
diff mbox

Patch

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a48712e..f8464ff 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1301,6 +1301,29 @@  config ARM_ERRATA_751472
 	  operation is received by a CPU before the ICIALLUIS has completed,
 	  potentially leading to corrupted entries in the cache or TLB.
 
+config ARM_ERRATA_794072
+	bool "ARM errata: A short loop including a DMB instruction might cause a denial of service"
+	depends on CPU_V7 && SMP
+	help
+	   This option enables the workaround for the 794072 Cortex-A9
+	   (all revisions). A processor which continuously executes a short
+	   loop containing a DMB instruction might prevent a CP15 operation
+	   broadcast by another processor making further progress, causing
+	   a denial of service. This erratum can be worked around by setting
+	   bit[4] of the undocumented Diagnostic Control Register to 1.
+
+config ARM_ERRATA_761320
+	bool "Full cache line writes to the same memory region from at least two processors might deadlock processor"
+	depends on CPU_V7 && SMP
+	help
+	  This option enables the workaround for the 761320 Cortex-A9 (r0..r3).
+	  Under very rare circumstances, full cache line writes
+	  from (at least) 2 processors on cache lines in hazard with
+	  other requests may cause arbitration issues in the SCU,
+	  leading to processor deadlock. This erratum can be
+	  worked around by setting bit[21] of the undocumented
+	  Diagnostic Control Register to 1.
+
 config PL310_ERRATA_753970
 	bool "PL310 errata: cache sync operation may be faulty"
 	depends on CACHE_PL310
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 5740296d..19690c2 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -794,6 +794,8 @@  config SOC_IMX6
 config SOC_IMX6Q
 	bool "i.MX6 Quad/DualLite support"
 	select ARM_ERRATA_764369 if SMP
+	select ARM_ERRATA_794072 if SMP
+	select ARM_ERRATA_761320 if SMP
 	select HAVE_ARM_SCU if SMP
 	select HAVE_ARM_TWD if SMP
 	select MIGHT_HAVE_PCI
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 195731d..b5e5386 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -337,6 +337,17 @@  __v7_setup:
 	mcrlt	p15, 0, r10, c15, c0, 1		@ write diagnostic register
 1:
 #endif
+#ifdef CONFIG_ARM_ERRATA_794072
+	mrc	p15, 0, r10, c15, c0, 1		@ read diagnostic register
+	orr	r10, r10, #1 << 4		@ set bit #4
+	mcr	p15, 0, r10, c15, c0, 1		@ write diagnostic register
+#endif
+#ifdef CONFIG_ARM_ERRATA_761320
+	cmp	r6, #0x40			@ present prior to r4p0
+	mrclt	p15, 0, r10, c15, c0, 1		@ read diagnostic register
+	orrlt	r10, r10, #1 << 21		@ set bit #21
+	mcrlt	p15, 0, r10, c15, c0, 1		@ write diagnostic register
+#endif
 
 	/* Cortex-A15 Errata */
 3:	ldr	r10, =0x00000c0f		@ Cortex-A15 primary part number